Update failed for Reader X, "another installation in progress". Tried both Adobe recommendations. In regedit, there was no in progress installation key to remove. Tried to unregister the windows installer service, gave error "another installation in progress".

Thank you for your help. I finally figured out that there must have been a camera attached to the computer at one time, and installations were referencing drive F:\. After using regedit to eliminate all references to that drive, I was allowed to unregister and reregister windows update services, which fixed the problem.